Detecting missing teeth on PMCT using statistical shape modeling.

The identification of teeth in 3D medical images can be a first step for victim identification from scant remains, for comparison of ante- and postmortem images or for other forensic investigations. We evaluate the performance of a tooth detection approach on mandibles with missing parts or pathologies based on statistical shape models. The proposed approach relies on a shape model that has been built from the full lower jaw, including the mandible and teeth. The model is fitted to the target, resulting in a reconstruction, in addition to a label map that indicates the presence or absence of teeth. We evaluate the accuracy of the proposed solution on a dataset consisting of 76 target mandibles, all extracted from CT images and exhibiting various cases of missing teeth or other cases, such as roots, implants, first dentition, and gap closure. We show an accuracy of approximately 90% on the front teeth (including incisors and canines in our study) that decreases for the molars due to high false-positive rates at the wisdom teeth level. Despite the drop in performance, the proposed approach can be used to obtain an estimate of the tooth count without wisdom teeth, tooth identification, reconstruction of the existing teeth to automate measurements taken as part of routine forensic procedures, or prediction of the missing teeth shape. In comparison to other approaches, our solution relies solely on shape information. This means it can be applied to cases obtained from either medical images or 3D scans because it does not depend on the imaging modality intensities. Another novelty is that the proposed solution avoids heuristics for the separation of teeth or for fitting individual tooth models. The solution is therefore not target-specific and can be directly applied to detect missing parts in other target organs using a shape model of the new target.

GD2 Expression in Medulloblastoma and Neuroblastoma for Personalized Immunotherapy: A Matter of Subtype.

Neuroblastoma (NBL) and medulloblastoma (MB) are aggressive pediatric cancers which can benefit from therapies targeting gangliosides. Therefore, we compared the ganglioside profile of 9 MB and 14 NBL samples by thin layer chromatography and mass spectrometry. NBL had the highest expression of GD2 (median 0.54 nmol GD2/mg protein), and also expressed complex gangliosides. GD2-low samples expressed GD1a and were more differentiated. MB mainly expressed GD2 (median 0.032 nmol GD2/mg protein) or GM3. Four sonic hedgehog-activated (SHH) as well as one group 4 and one group 3 MBs were GD2-positive. Two group 3 MB samples were GD2-negative but GM3-positive. N-glycolyl neuraminic acid-containing GM3 was neither detected in NBL nor MB by mass spectrometry. Furthermore, a GD2-phenotype predicting two-gene signature (ST8SIA1 and B4GALNT1) was applied to RNA-Seq datasets, including 86 MBs and validated by qRT-PCR. The signature values were decreased in group 3 and wingless-activated (WNT) compared to SHH and group 4 MBs. These results suggest that while NBL is GD2-positive, only some MB patients can benefit from a GD2-directed therapy. The expression of genes involved in the ganglioside synthesis may allow the identification of GD2-positive MBs. Finally, the ganglioside profile may reflect the differentiation status in NBL and could help to define MB subtypes.

Reconstruction of full femora from partial bone fragments for anthropological analyses using statistical shape modeling.

OBJECTIVES: Due to taphonomic processes such as burial, fire, or animal activity, bones are often found incomplete, which can pose problematic for establishing the biological profile of the deceased using anthropological methods. The aim of this study is to test the feasibility of using statistical shape modeling (SSM) to reconstruct full femora from simulated partial femora and determine the accuracy of the reconstruction. Moreover, we assess the accuracy of sex estimation and the degree of stature error added based on the reconstructed femur using different anthropological methods. METHODS: A total of 42 (28 female, 14 female) 3D models of left femora extracted from computed tomography (CT) scans were used. We performed a leave-one-out cross-validation (LOOCV) where 41 bones were used to build the SSM and one bone was used for testing. This bone was cut in 1 cm steps proximally, distally and from both ends up to 10 cm, reconstructed using SSM, and tested using the methods established by Stewart and Purkait (2005), Trotter and Gleser (1952), as well as a method based on SSM. with landmarks being automatically identified. RESULTS: The error induced by reconstructing the femur to the length measurements was low, which translated into useful stature estimations (single sided cuts up to 10 cm: 0.4-1.1%, double sided<2% for cuts shorter than 6 cm). Using Purkaits method for sex estimation on reconstructed bones looked promising as well (single sided: 90.5% when compared to applying Purkaits method on the original bone, double sided 78.6% (10 cm cut) to 97.6% (1-3 cm cuts)) Using SSM for sex classification looked promising as well (single sided cut: 81-85.7%, double sided cut: 59.5-85.3%) CONCLUSION: SSM can be used to reconstruct fragmented femora. These reconstructions can be used for sex and stature estimations, at the cost of lower accuracy. Using SSM might give investigators an additional tool to gain information about the biological profile of a deceased in cases where the fragmentation of a femur does not allow for using other anthropological methods.

Clinical forensic height measurements on injured people using a multi camera device for 3D documentation.

Documenting the existence, size, position and shape of injuries is an important part of medical forensic examinations. In the photography of an injury, the documentation is limited to an approximation of size and position of the injury based on a ruler included in the image. The documentation of injuries can be improved with photogrammetry, which allows the creation of scaled 3D models of an injury that can be used to not only document and visualize the injury but also to match the injury with an injury-causing object. In this paper, the multicamera device "Botscan" was used to perform 3D whole-body documentation and measure the positions of injuries. A major advantage of 3D whole-body documentation compared to photography is that the former can be performed at a later stage of the investigation. This makes the whole-body 3D documentation of injuries an important tool for re-examination.

Pseudolesion in the right parafissural liver parenchyma on CT: The base is found in embryology and collagen content.

BACKGROUND: Computed tomography (CT) images of livers may show a hypo-attenuated structure alongside the falciform ligament, which can be a focal fatty pseudolesion and can mimic a malignancy. The preferred location is on the right parafissural site, ventral in segment IVa/b. The etiology is not clear, nor is it known how the histology of this location develops. These are evaluated in this study. METHODS: 40 adult cadavers with autopsy and / or postmortem CT in a university hospital and a forensic center were included. Liver biopsies were taken at the left side of the falciform ligament as control, and at the right side as the possible precursor of a pseudolesion; these were examined for collagen and fat content. Cadavers with steatotic (>5% fat) or fibrotic (>2% collagen) control samples were excluded. RESULTS: Significantly more collagen was present in the right parafissural liver parenchyma: median 0.68% (IQR: 0.32-1.17%), compared to the left side 0.48% (IQR: 0.21-0.75%) (p 0.008), with equal fat content and CT attenuation values. The etiophysiology goes back to the demise of the umbilical venes in the early embryonic and neonatal period. CONCLUSIONS: The right parafissural area contains more collagen and an equal amount of fat compared to the control left side. This supports the hypothesis of delayed, 'third' inflow: the postnatal change in blood supply from umbilical to portal leaves the downstream parafissural area hypoperfused leading to hypoxia which in turn results in collagen accumulation and the persistence of paraumbilical veins of Sappey.

Rapid death following undiagnosed stercoral perforation in a chronic opioid user.

A case of rapid demise following an undiagnosed stercoral perforation is reported. A 57-year-old woman on chronic opioid replacement therapy presented with constipation and abdominal pain to the hospital. Following an unremarkable abdominal radiograph and admission for laxation and pain therapy, she was found dead only 18 h later. To exclude medical malpractice, a postmortem investigation was ordered. Postmortem computed tomography and autopsy revealed fatal fecal peritonitis based on a stercoral perforation of the rectosigmoid, which had been undiagnosed. This report highlights the need for early cross-sectional imaging and contributes to the data collection concerning this ever-growing, vulnerable group of patients undergoing opioid replacement.

Postmortem imaging of perimortem skeletal trauma.

Various imaging modalities, including conventional radiography, computed tomography, magnetic resonance, and surface scanning have been applied in the examination of skeletal injuries in the forensic context. Although still not a substitute for a full medico-legal autopsy or the examination of skeletal remains, imaging is now increasingly used as a complementary tool in the postmortem analysis of perimortem skeletal trauma. Facilitated by the progress in general computational capacity, multimodal imaging has been proposed for comprehensive forensic documentation. A major advantage of these imaging approaches is that stored digital or physical 3D models of skeletal injuries can be reviewed at any time by various experts as well as be presented in court as evidence to clarify potentially complex medical and forensic aspects of the case. Due to constant technical progress in imaging techniques and software, continuous education, training, and sharing of expertise among engineers, computer scientists, and forensic experts, including forensic pathologists, anthropologists, and radiologists needs to be warranted to maintain high-quality expertise in the detection and interpretation of traumatic injuries on postmortem imaging. The technical developments and ever-improving user-friendliness of 3D imaging and modeling techniques present an atttactive alternative to traditional forensic approaches, but as long as the techniques have not been sufficiently tested and validated for forensic trauma analysis, and best practice manuals for forensic practice are lacking for both the technical procedures and method selection, the use of imaging techniques needs to be reevaluated on a case-by-case basis. In addition, ethical, legal, and financial aspects of the use of imaging and 3D modeling for forensic purposes need to be well understood by all parties in legal proceedings.

Fatal bilateral pneumothorax and generalized emphysema following contraindicated speaking-valve application.

We report a case of a contraindicated attachment of a speaking valve to a tracheal tube with an inflated cuff, which rapidly resulted in the patient's death. The attached one-way valve allowed unrestrained inspiration through the tracheal tube but prevented physiological expiration. The increased pulmonary pressure resulted in alveolar rupture and replaced expiration with a steady release of air into the peribronchial sheaths and the mediastinum, resulting in what is commonly known as the Macklin effect. From the mediastinum, air inflated both pleural cavities, the peritoneum, and the subcutaneous tissue of the entire body. No gas was found in the blood vessels, the brain, the bones, or in the inner organs. The entire air volume was estimated by radiological segmentation to be more than 25 l. This implies continuous inspiration, while expiration turned into an aberrant pulmonary decompression by whole-body gas-enclosure. Death ultimately resulted from asphyxia following bilateral (tension) pneumothorax.

CT-based sex estimation on human femora using statistical shape modeling.

OBJECTIVES: Estimating the sex of decomposed corpses and skeletal remains of unknown individuals is one of the first steps in the identification process in forensic contexts. Although various studies have considered the femur for sex estimation, the focus has primarily been on a specific single or a handful of measurements rather than the entire shape of the bone. In this article, we use statistical shape modeling (SSM) for sex estimation. We hypothesize that the accuracy of sex estimation will be improved by using the entire shape. MATERIALS AND METHODS: For this study, we acquired a total of 61 femora from routine postmortem CT scans at the Institute for Forensic Medicine of the University of Zurich. The femora were extracted using segmentation technique. After building a SSM, we used the linear regression and nonlinear support vector machine technique for classification. RESULTS: Using linear logistic regression and only the first principal component of the SSM, 76% of the femora were correctly classified by sex. Using the first five principal components, this value could be increased to 80%. Using nonlinear support vector machines and the first 20 principal components increased the rate of correctly classified femora to 87%. DISCUSSION: Despite some limitations, the results obtained by using SSM for sex estimation in femur were promising and confirm the findings of other studies. Sex estimation accuracy, however, is not significantly improved over single or multiple linear measurements. Further research might improve the sex determination process in forensic anthropology by using SSM.

Detection of elevated ketone bodies by postmortem 1H-MRS in a case of fetal ketoacidosis.

We report a fetal loss following maternal ketoacidosis in a case of cryptic pregnancy. Biochemical analysis of peripheral blood revealed highly elevated levels of beta-hydroxybutyrate (BHB) in the mother (9.2 mmol/l) and the fetus (4.2 mmol/l). Fetal ketoacidosis with hypoxic-ischemic brain damage was determined to be the cause of death. 1H-MRS of the right cerebral hemisphere presented with distinctive resonances of BHB and acetone. Acetoacetate and glucose were not detected. Due to reported chronic abuse of ethanol and a period of fasting, alcoholic ketoacidosis was concluded to be the cause of the metabolic disorder. 1H-MRS is a viable examination for the postmortem detection of ketone bodies and may be a key supplement to noninvasive fetal autopsy for the diagnosis of ketoacidosis.

Pandora's box.

Suitcases or other containers are occasionally involved in forensic investigations. If there is a suspicion that human remains are hidden inside such a container, medico-legal examinations are required. However, these containers are occasionally locked. Forced opening of a locked suitcase or container may cause damage to its contents. Additionally, the safety of the investigator has to be considered as such containers may be booby-trapped or contain other hazardous material. An overview of the contents before opening is desirable in order to avoid the possibility of encountering a Pandora's box. In forensic medicine, an established approach to examine the inside of a body before opening at autopsy is postmortem computed tomography (CT). However, there may be a reluctance to use this approach for suitcases or containers with metallic components because of the assumption that severe metal artifacts will result in inadequate images. In this article, we present a forensic case in which a CT scan of a metallic suitcase was performed in order to examine its contents. Additionally, we performed an experimental scan of a conventional safe in order to determine if CT is able to reveal the contents of such a highly radiopaque storage box.

The gas bubble sign-a reliable indicator of laryngeal fractures in hanging on post-mortem CT.

OBJECTIVE: The purpose was to evaluate the presence of gas in the tissue adjacent to the laryngeal structures, "the gas bubble sign", in cases of hanging as a diagnostic indicator of neck trauma. METHODS: In this study, post-mortem CT (PMCT) scans and autopsies of 35 victims of hanging were examined to reveal age-dependent changes, laryngeal fracture, fracture location and the presence of gas. A matched group with cardiac arrest or intoxication was used as controls (n = 35). An autopsy was performed in each case. RESULTS: Incomplete suspension was the most common method in hanging. The thyroid horns (90.5%) were identified as the most vulnerable location for fractures. Laryngeal deformity and dislocation, which was only detected on PMCT, was observed in 57.1% and was concomitant with fractures in 83.3%. Laryngeal fractures are more common with advanced age (>40 years, 88.9%) and less common in younger subjects (<40 years, 29.4%). The gas bubble sign with regard to laryngeal fractures yielded a sensitivity of 79.2%, a positive predictive value of 95%, a specificity of 90.9%, a negative predictive value of 34.5% and an accuracy of 83%. CONCLUSION: The complex evaluation of the larynx is profoundly supported by PMCT and the detection of the gas bubble sign as a diagnostic indicator of neck trauma. This relevant diagnostic finding might aid in not only post-mortem cases but also clinical cases, for patients who survive an assault to the neck. Advances in knowledge: (1) The gas bubble sign is a diagnostic indicator of neck trauma in not putrefied bodies. (2) PMCT supports evaluation of trauma to the neck in hanging tremendously. (3) The diagnostic finding of gas located at the laryngeal structures may not only aid in post-mortem cases but also clinical cases of people who survive an assault to the neck.

Fatal bronchovascular fistula after lobectomy visualized through postmortem computed tomography angiography: A case report.

False aneurysm of the pulmonary artery complicated by bronchovascular fistula formation represents a rare life threating condition. We report a case of fatal hemoptysis after formation of a bronchial fistula in the late postoperative period after sleeve lobectomy. Cause of death was determined by external postmortem examination, post mortem computed tomography (PMCT) and angiography (PMCTA) without conventional autopsy.